Saves us one cycle of alloc-add-free if the queue was full.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (modified)
Now we can tell the theoretical capacity remaining in the output
queue, virtio_net can waste entries by stopping the queue early.
It doesn't work in the case of indirect buffers and kmalloc failure,
but that's rare (we could drop the packet in that case, but other
drivers return TX_BUSY for similar reasons).
For the record, I think this patch reflects poorly on the linux
network API.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Dinesh Subhraveti <dineshs@us.ibm.com>
We put the virtio_net_hdr into the skb's cb region; turn this into a
union to clean up the code slightly and allow future expansion.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Mark McLoughlin <markmc@redhat.com>
Cc: Dinesh Subhraveti <dineshs@us.ibm.com>
The virtio_net driver is complicated by the two methods of freeing old
xmit buffers (in addition to freeing old ones at the start of the xmit
path).
The original code used a 1/10 second timer attached to xmit_free(),
reset on every xmit. Before we orphaned skbs on xmit, the
transmitting userspace could block with a full socket until the timer
fired, the skb destructor was called, and they were re-woken.
So we added the VIRTIO_F_NOTIFY_ON_EMPTY feature: supporting devices
send an interrupt (even if normally suppressed) on an empty xmit ring
which makes us schedule xmit_tasklet(). This was a benchmark win.
Unfortunately, VIRTIO_F_NOTIFY_ON_EMPTY makes quite a lot of work: a
host which is faster than the guest will fire the interrupt every xmit
packet (slowing the guest down further). Attempting mitigation in the
host adds overhead of userspace timers (possibly with the additional
pain of signals), and risks increasing latency anyway if you get it
wrong.
In practice, this effect was masked by benchmarks which take advantage
of GSO (with its inherent transmit batching), but it's still there.
Now we orphan xmitted skbs, the pressure is off: remove both paths and
no longer request VIRTIO_F_NOTIFY_ON_EMPTY. Note that the current
QEMU will notify us even if we don't negotiate this feature (legal,
but suboptimal); a patch is outstanding to improve that.
Move the skb_orphan/nf_reset to after we've done the send and notified
the other end, for a slight optimization.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Mark McLoughlin <markmc@redhat.com>
This effectively reverts 99ffc696d1
"virtio: wean net driver off NETDEV_TX_BUSY".
The complexity of queuing an skb (setting a tasklet to re-xmit) is
questionable, especially once we get rid of the other reason for the
tasklet in the next patch.
If the skb won't fit in the tx queue, just return NETDEV_TX_BUSY.
This is frowned upon, so a followup patch uses a more complex solution.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
The complex transmit free logic was introduced to avoid hangs on
removing the ip_conntrack module and also because drivers aren't
generally supposed to keep stale skbs for unbounded times.
After some debate, it was decided that while doing skb_orphan()
generally is a rat's nest, we can do it in this driver. Following
patches take advantage of this.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The new ones have pretty kerneldoc. Move the old ones to the end to
avoid confusing people.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: benh@kernel.crashing.org
We're not forcing removal of the old cpu_ functions, but we might as
well delete the now-unused ones.
Especially CPUMASK_ALLOC and friends. I actually got a phone call (!)
from a hacker who thought I had introduced them as the new cpumask
API. He seemed bewildered that I had lost all taste.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: benh@kernel.crashing.org
Makes code futureproof against the impending change to mm->cpu_vm_mask (to be a pointer).
It's also a chance to use the new cpumask_ ops which take a pointer
(the older ones are deprecated, but there's no hurry for arch code).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Makes code futureproof against the impending change to mm->cpu_vm_mask.
It's also a chance to use the new cpumask_ ops which take a pointer
(the older ones are deprecated, but there's no hurry for arch code).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Makes code futureproof against the impending change to mm->cpu_vm_mask.
It's also a chance to use the new cpumask_ ops which take a pointer
(the older ones are deprecated, but there's no hurry for arch code).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Makes code futureproof against the impending change to mm->cpu_vm_mask
(to be a pointer).
It's also a chance to use the new cpumask_ ops which take a pointer
(the older ones are deprecated, but there's no hurry for arch code).
Also change the actual arg name here to "mm" (which it is), not "task".
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Makes code futureproof against the impending change to mm->cpu_vm_mask.
It's also a chance to use the new cpumask_ ops which take a pointer
(the older ones are deprecated, but there's no hurry for arch code).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Hirokazu Takata <takata@linux-m32r.org> (fixes)
Makes code futureproof against the impending change to mm->cpu_vm_mask.
It's also a chance to use the new cpumask_ ops which take a pointer
(the older ones are deprecated, but there's no hurry for arch code).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Use the accessors rather than frobbing bits directly (the new versions
are const).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Use the accessors rather than frobbing bits directly (the new versions
are const).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Use the accessors rather than frobbing bits directly (the new versions
are const).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Use the accessors rather than frobbing bits directly (the new versions
are const).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
We're weaning the core code off handing cpumask's around on-stack.
This introduces arch_send_call_function_ipi_mask().
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We're weaning the core code off handing cpumask's around on-stack.
This introduces arch_send_call_function_ipi_mask(), and by defining
it, the old arch_send_call_function_ipi is defined by the core code.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We're weaning the core code off handing cpumask's around on-stack.
This introduces arch_send_call_function_ipi_mask(), and by defining
it, the old arch_send_call_function_ipi is defined by the core code.
We also take the chance to wean the implementations off the
obsolescent for_each_cpu_mask(): making send_ipi_mask take the pointer
seemed the most natural way to ensure all implementations used
for_each_cpu.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We're weaning the core code off handing cpumask's around on-stack.
This introduces arch_send_call_function_ipi_mask(), and by defining
it, the old arch_send_call_function_ipi is defined by the core code.
We also take the chance to wean the implementations off the
obsolescent for_each_cpu_mask(): making send_ipi_mask take the pointer
seemed the most natural way to ensure all implementations used
for_each_cpu.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We're weaning the core code off handing cpumask's around on-stack.
This introduces arch_send_call_function_ipi_mask().
We also take the chance to wean the send_ipi_message off the
obsolescent for_each_cpu_mask(): making it take a pointer seemed the
most natural way to do this.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
smp_call_function_many is the new version: it takes a pointer. Also,
use mm accessor macro while we're changing this.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
set_cpus_allowed() is on the way out; replace it with
set_cpus_allowed_ptr().
Reference: http://lkml.org/lkml/2008/11/6/448
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
By 7be23e278f, mask field was deleted by irqaction. However, it was not
deleted from comment.
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Up until 1.1.83, the primitive human tribes used struct sigaction for
interrupts. The sa_mask field was overloaded to hold a pointer to the
name.
When someone created the new "struct irqaction" they carried across
the "mask" field as a kind of ancestor worship: the fact that it was
unused makes clear its spiritual significance.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
(Thanks to Al Viro for reminding me of this, via Ingo)
CPU_MASK_ALL is the (deprecated) "all bits set" cpumask, defined as so:
#define CPU_MASK_ALL (cpumask_t) { { ... } }
Taking the address of such a temporary is questionable at best,
unfortunately 321a8e9d (cpumask: add CPU_MASK_ALL_PTR macro) added
CPU_MASK_ALL_PTR:
#define CPU_MASK_ALL_PTR (&CPU_MASK_ALL)
Which formalizes this practice. One day gcc could bite us over this
usage (though we seem to have gotten away with it so far).
So replace everywhere which used &CPU_MASK_ALL or CPU_MASK_ALL_PTR
with the modern "cpu_all_mask" (a real struct cpumask *), and remove
CPU_MASK_ALL_PTR altogether.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Ingo Molnar <mingo@elte.hu>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mike Travis <travis@sgi.com>
(Thanks to Al Viro for reminding me of this, via Ingo)
CPU_MASK_ALL is the (deprecated) "all bits set" cpumask, defined as so:
#define CPU_MASK_ALL (cpumask_t) { { ... } }
Taking the address of such a temporary is questionable at best,
unfortunately 321a8e9d (cpumask: add CPU_MASK_ALL_PTR macro) added
CPU_MASK_ALL_PTR:
#define CPU_MASK_ALL_PTR (&CPU_MASK_ALL)
Which formalizes this practice. One day gcc could bite us over this
usage (though we seem to have gotten away with it so far).
Now all callers are removed, we kill it.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Ingo Molnar <mingo@elte.hu>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mike Travis <travis@sgi.com>
Remove open-coded zalloc_cpumask_var() and zalloc_cpumask_var_node().
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next: (30 commits)
Use macros for .data.page_aligned section.
Use macros for .bss.page_aligned section.
Use new __init_task_data macro in arch init_task.c files.
kbuild: Don't define ALIGN and ENTRY when preprocessing linker scripts.
arm, cris, mips, sparc, powerpc, um, xtensa: fix build with bash 4.0
kbuild: add static to prototypes
kbuild: fail build if recordmcount.pl fails
kbuild: set -fconserve-stack option for gcc 4.5
kbuild: echo the record_mcount command
gconfig: disable "typeahead find" search in treeviews
kbuild: fix cc1 options check to ensure we do not use -fPIC when compiling
checkincludes.pl: add option to remove duplicates in place
markup_oops: use modinfo to avoid confusion with underscored module names
checkincludes.pl: provide usage helper
checkincludes.pl: close file as soon as we're done with it
ctags: usability fix
kernel hacking: move STRIP_ASM_SYMS from General
gitignore usr/initramfs_data.cpio.bz2 and usr/initramfs_data.cpio.lzma
kbuild: Check if linker supports the -X option
kbuild: introduce ld-option
...
Fix trivial conflict in scripts/basic/fixdep.c
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
NFS: Propagate 'fsc' mount option through automounts
sunrpc/rpc_pipe: fix kernel-doc notation
sunrpc: xdr_xcode_hyper helpers cannot presume 64-bit alignment
NFS: Add nfs_alloc_parsed_mount_data
NFS/RPC: fix problems with reestablish_timeout and related code.
NFS: Get rid of the NFS_MOUNT_VER3 and NFS_MOUNT_TCP flags
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
9p: Update documentation to add fscache related bits
9p: Add fscache support to 9p
9p: Fix the incorrect update of inode size in v9fs_file_write()
9p: Use the i_size_[read, write]() macros instead of using inode->i_size directly.
